A retainer, also commonly referred to as a cage, is a common component in bearings, constant-velocity joints, and other types of rotary couplings that include a plurality of rolling elements. A retainer typically includes pockets that constrain the rolling elements to maintain a desired angular spacing between the rolling elements.
Conventional retainers are made from a variety of materials in order to suit a particular application and production volume. For example, when production volume is high, retainers are typically made of steel or polymers. When production volume is low, retainers are typically made of brass or bronze. Additionally, brass and bronze offer superior tribological (i.e., lubrication and wear) characteristics compared to steel.
Conventional retainers are made by a variety of manufacturing processes in order to suit a particular production volume. For high-volume manufacturing, retainers can be manufactured by a stamping process for steels or by an injection molding process for polymers. These processes can produce parts quickly and relatively inexpensively, but they require large initial tooling investments. As such, these processes are riot suitable for low-volume manufacturing. For low-volume manufacturing, retainers can be machined from a solid block casting or rolled forging. Although machining requires less tooling investment, it can be time consuming and expensive.